Five Killer Patents

Five Killer Patents

Untangling Nanotech’s PotentialPatent No. 6,645,455Rice UniversityINVENTION: A method for separating and chemically modifying carbon nanotubes BENEFIT: Could make it easier to use nanotubes in superstrong materials, bright, low-power displays, or ultrasensitive biosensors

Carbon nanotubes are the poster molecules of the nanotech revolution-strong, electronically versatile, and no wider than a strand of DNA. They could enable everything from supertough, lightweight materials to ultrasensitive medical diagnostic tests. In their raw state, though, nanotubes tend to clump together in bunches, which makes it difficult to take full advantage of their extraordinary properties. But in the first of a series of inventions aimed at unlocking nanotubes’ potential, researchers at Rice University have devised a simple way to untangle and separate them.

The technique involves some straightforward chemistry. Led by Robert Hauge and the late John Margrave, the Rice chemists first exposed carbon nanotubes to fluorine gas. The fluorine binds to the sides of the tubes, making them less sticky and allowing them to be separated from each other. This makes it easier to incorporate the nanotubes into materials, whose strength or electrical conductivity can improve as a result; it is also a key step in using single nanotubes as parts of nanoelectronic devices. “If you want to use nanotubes one by one, you’re going to have to do something to the sides, and this allows you to do that,” says Richard E. Smalley, a Nobel laureate Rice chemist who collaborated on the work.

Houston-based Rice spinoff CNI, which was cofounded by Smalley, is using the patented technique to modify manufactured batches of the nanotubes that it sells to academic and corporate researchers. While the company is mum on the details of its collaborative efforts to exploit nanotubes, the new separation technique could help the molecules fulfill their revolutionary promise. -Erika Jonietz